#include<stdio.h>

void swap(int *u, int *v);

int main(void) {
    int a = 5, b = 10;

    printf("Originally: a = %d, b = %d\n", a, b);
    swap(&a, &b);
    printf("Now: a = %d, b = %d\n", a, b);

    return 0;
}

void swap(int *u, int *v) {

    int temp = *u;
    *u = *v;
    *v = temp;

}